Help:Images formats
= Image formats for the wiki = Only certain image formats can be included into the wiki. A list is given on the upload page . The most important image formats are: * png, * gif, * jpg/jpeg Which format is the best for your image depends from case to case. PNG format Key features: * Lossless compression scheme. No reduction of image quality. * Supports full color range. * Supports full and semi-transparency (alpha channel). This format always provides a very good image quality, because you never loose some information. It works very well for artificial graphics. But it tends to creates huge files sizes for noisy images like real photos, which are inappropriate for web pages. GIF format Key features: * Supports only up to 256 colors. These colors can be selected freely within the full color range and are stored in a palette which is included in the image. * Supports animations. These have to be created with a special program, because most image manipulation programs do not have support for it. * Support for full transparency. This format is good for most screenshots from Dan-Ball games. Most of these screenshots do not contain more than 256 colors, and therefore the GIF format can provide a lossless compression. Most image programs have the possibility to count the number of colors. If the image contains more than 256 colors you will lose some image quality if you use the GIF format. In some cases this might be acceptable but usually you should consider using the PNG format instead. You should not use the GIF format for photos or similar images. If you save the image or reduce the number of colors to 256 make sure you have selected to use a custom or optimized palette, and do not use the setting standard palette, web-optimized palette or web-save palette. If your original image contains more than 256 colors it's important to choose the right method for color selection. Usually you should use a setting called Octree optimized because this setting chooses good color palette based on how often a certain color is used for the pixels, but it does not forget to include some extreme colors even if they only appear for a few pixels. Also you can choose between some settings for the color reduction: Nearest color will work if you don't have to much colors above the number of 256, otherwise it creates banding artefacts for some smooth color gradients and other bad effects. Error diffusion will introduce some noice and is usually better if the original image contains noise anyway. You have to choose from case to case wheather nearest color or error diffusion gives better results. Not all of those settings might be accessible in your image program. Some programs don't provide access at all, while in some programs they are hidden in special setting windows for the GIF format or behind some buttons in the save dialog. Sometimes you can only access them if you reduce the color depth on your own before you save the image. JPG/JPEG format Key features: * Uses a lossy compression. You might lose some image quality. * Supports full color range. * Very good compression scheme for photos or similar pictures. * A bad compression scheme for artifical graphics which have only few colors. Especially sharp features get blured, or you get some color bleeding effects. It is important that you choose the degree of compression wisely, otherwise you get blocky artefact, sharp features get blured, or you get some color bleeding effects. Also some colors don't look saturated anymore. You should not use it for screenshots from any of the 2D dan-ball games. Category:Help